trouble-free operation

безвідмовна робота; безаварійна експлуатація; безаварійна робота

accident-free flying / mishap-free flying

mishap-free flying / accident-free flying

potential danger area (trouble area)

extraction trouble

cause of aircraft trouble

ignition trouble

knock-free operation

accident-free operation

failure-free operation

free-flier operation

clandestine operation; covert operation

humanitarian operation; humanitarian relief operation (HUMRO)

PZ operation (pick-up zone operation)

noncombatant evacuation operation (NEO); non-combat evacuation operation

contact-free war

contamination-free

free fall air drop

free naval control of shipping

nuclear-free zone

toxic free area